Do not replace the lower jockey wheel with a spare upper you happen to have lying about. I now know that it has “upper pulley” written on it for a very good reason! 🙁

spokey spokey ping ping?

Somehow the wheel survived. Cage in two pieces though and a properly bent hanger. I’ve got quite a collection of broken x0 mechs now.

😥

29er SS phatbiker will be along any mo now, to tell you where you really went wrong 😀

How can changing a pulley cause a derailleur to disintegrate? Genuinely interested!

Because when fitted to the lower position, an upper pulley has enough side to side play in it to allow the chain to foul the derailleur cage, get caught, and promptly make a mess of it’s underpants.

Shortly before it happened my chain was skipping a bit (by pulling the catoad reared then jumping back) and I stopped to have a look at it. Got talking to a chap who also fitted an upper in the lower position and he said his dereillieur exploded. About a minute later mine exploded. He’d said it was something to do with slightly different profiles or widths or something like that.

Edit: Oggles that sounds about right. Did make quite a mess.

Any intact medium x0 cages in your collection mrblobby?

Same thing happens if you let the lower jockey wheel get too worn 😳

Any intact medium x0 cages in your collection mrblobby?

Unfortunately not, just 3 bodies now and a bunch of split cages 🙁

here’s my top tip for people with X0 mechs…

when it wears out or you break it, buy x9 instead.

Sram X0 2011 10sp rear mech
RRP: £209 (can be had for £145 online)
weight: 190gm

Sram X9 2011 10sp rear mech
RRP: £99 (can be had for £59 online)
weight: 204gm

so seriously is it actually worth £100 extra to save 10g?
and even *if* the X0 shifts slightly better and lasts slightly longer – which has not been my experience after having had both X0 and X9 mechs – then it still works out better to just buy X9 slightly more often (or keep a spare at home)

Funnily enough that’s exactly what I’ve done!

when it wears out or you break it, buy x9 instead.

yup, precisely what I plan to do and and when the 5 year old X0 bites the dust…..